Hydraulic and pneumatic door closures for controlling closing characteristics of swing doors are well known and have been widely used. See, for example, U.S. Pat. Nos. 4,793,023, 4,414,703 and 4,378,612. Primarily hydraulically, pneumatically operated openers, or opening assist mechanisms are also known. U.S. Pat. Nos. 3,948,000, 3,936,977, 4,955,194 and 4,429,490 teach such mechanisms. Additionally, a variety of electromechanical automatic door operators are known. See, for example, U.S. Pat. Nos. 2,910,290, 3,127,160, 4,045,914 and 4,220,051. Each type of door opener, hydraulic, pneumatic and electromechanical, has its own advantages and disadvantages.
It has also been known to combine these mechanisms in order to obtain some of the advantages of each. See, for example, U.S. Pat. Nos. 3,874,117, 3,129,936, 1,684,704, 2,256,613, and 4,438,835. This approach to making door controllers has sometimes included using an hydraulic mechanism merely as a speed controller rather than as an independently functioning unit. This approach is not entirely satisfactory due to a lack of attractiveness and additional space requirements adjacent to the door. Additionally, the expense of manufacture and operation is relatively high for some combinations. For example, when a clutch or other disengagement mechanism is required for operation, the resulting system can be too expensive for economical use. Furthermore, excessive control complexity may be required to achieve reliability and to meet door operating standards for some combinations.
Previous door operating systems required an individual to perform calibrations to monitor the movement and location of a door. Installation of such door systems were tedious, cumbersome and time consuming because most door system computers did not know the location of the door or were not able to continuously monitor the movement of the door. In addition, most door operating systems did not have any features that accommodated obstacles and the changing conditions of obstacles. For example, a carpet underneath a door operated by such a system can be flat, shaggy, etc. and can undergo numerous changes based on heat, moisture, etc. When wet, the carpet is flatter and movement of the door is easier. When dry and hot, the carpet material has a propensity to expand and movement of the door may be restricted. The prior art door systems could not self-adjust to these conditions.
In addition, most door operating systems are not able to function during power outages. Since most door operating system situated in public facilities such as hospitals, the loss of power renders these door systems paralyzed and useless. The present invention addresses these problems by providing an improved door operating system.